Horror rappers Insane Clown Posse have taken legal action against officials at the U.S. Federal Bureau of Investigation after their face-painted fans were added to the organization's National Gang Threat Assessment list.

The group's followers, dubbed 'Juggalos', were classified as a gang in the bureau's 2011 update for exhibiting thug-like behaviour and undertaking alleged criminal activity. The report stated that most Juggalo-related crime is "sporadic, disorganised, individualistic" and involves "simple assault, personal drug use and possession, petty theft and vandalism".

The findings infuriated members of the group, who threatened to take action over the allegations - and on Tuesday, their legal team filed papers against the FBI at the U.S. District Court for the Eastern District of Michigan.

A post on the band's website reads, "Listen up, Homies! This is the biggest thing to rock the Juggalo and Juggalette universe... The Insane Clown Posse and (record label) Psychopathic Records have kept their word and filed a lawsuit against the FBI on behalf of the Juggalo Family TODAY!

"(The bandmembers) said they would be fightin' for the family's rights no matter how much time or money it took! And now today, September 25th, 2012, ICP and Psychopathic have made those promises a reality by officially filing their lawsuit against the FBI!

"The idea of calling the Juggalos and Juggalettes a 'gang' is straight up bulls**t. We are not a gang! We are a family! We come together for our luv (sic) of the Insane Clown Posse, Psychopathic Records, and our Juggalo pride. Can we take a f**kin' second to note that Jimmy Buffet's Parrot Heads, Lady Gaga's Little Monsters, Justin Bieber's Beliebers, the Grateful Dead's DeadHeads and many more haven't been labeled as a gang?

"Really, this is the first time in the history of rock-n-roll that any music fans have been labeled as a 'gang' and that's probably because it makes no damn sense! Juggalos are fans of music - not hardened, organized gang members! And that is why the Insane Clown Posse, Psychopathic Records, and their legal team are fighting for YOU!"